Here is a detailed tutorial on backing up your iPad if you intend to install system 7 tomorrow.
I have several iPads and I plan to wait a bit for the iPad retina and longer for my iPad 2. My greatest concern is that the iPad 2 may not have the power to provide a good experience and I will wait to see how others react. The delay will be difficult, but I plan to use some form of distraction like going to teach my classes to allow time to pass.